Block-signal system.



E. F. BLISS.

BLOCK SIGNAL SYSTEM.

APPLICATION FILED AUG. s. 190B.

m0872917, Patented Feb. 24, 1914.

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animan san/,iras PATENT onirica ELMER F. BLISS, OF SCI-IENECTADY, NEW' YORK, ASSIGNOR, BY IVIESNE ASSIGNMENTS,

TO THE UNION SWITCH AND SIGNAL COMPANY, A CORPORATION OF PENNSYL- VANIA.

BLOCK-SIGNAL SYSTEM.

To @ZZ whom t may concern Be it known that I, ELMER F. BLISS, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Block-Signal Systems, of which the following is a speciication.

My invention relates to block signal systems of the normal danger type, and its object is to provide an efficient and reliable system of this character having few line wires and small amount of apparatus.

Normal danger signal systems are ordi narily arranged with home and distant signals, or their equivalents, for giving danger, caution and clear indications. When a train enters a block, the home signal of the block in advance should clear, if that block is unoccupied, and the clearing of the home sig-` nal in advance should clear the home signal of the second block in advance, provided that the second block in advance is also nnoccupied; and the clearing of the latter home signal should clear the distant signal for the first block in advance. It is common practice to control the home signal of a block through a front contact of the track relay for that block and a back contact of the track relay for the block in the rear, and this arrangement I employ in my system. For producing the other signal operations, many different arrangements have been produced heretofore. For producing these other operations in my system I provide a contact controlled by the movement of a signal from danger to close a shunt circuit for the back contacts of the track relay for that block, so as to energize the relay for the block in advance that controls the home signal for the block in advance, and provide means for preventing the closing of the contact on the signal in advance from closing the shunt circuit for the back contacts of the track relay for the block in advance.

More specilically stated, I provide each block with a pair of relays responsive to different current strengths, the relay respond ing to the lesser current being the one which Specification of Letters Patent.

Application filed August 3, 1908.

Patented Feb. 24, 1914. serial No. 446,517.

controls the home signal, and provide a circuit for each of the pairs of relays extending through the block in the rear, which circuit is arranged to be closed through a low reslstance connection by a back contact of the track relay in the rear, or through a high resistance connection by a contact on the signal in the rear, and by a contact of the neutral relay in the rear which responds to the greater current. Furthermore, I insert a polarized relay in the high resistance connection, which relay controls the distant signal, and I place a reversing switch in the circuit controlled by the signal mechanism neXt in advance.

My invention will best be understood by reference to the accompanying drawing, which shows diagrammatically a normal danger block signal system arranged in accordance with my invention.

In the drawing A, A1 and A2 represent the rails of three adjacent blocks, which, with the track relays B, B1 and B2, and the track batteries Z9, form Clo-sed track circuits. The blocks are shown provided with home and distant signals, which, for block A, are represented by H and D.

C and E represent a pair of neutral relays, which are connected in series, but arranged to respond to different current strengths. This may be accomplished by using relays of different numbers of tnrns,-- or in other words, of different resistances. The relay C may be a 150 ohm relay, and relay E may be a 9 or 10 ohm relay. The relay C, which responds to the lesser current, has its contacts arranged to control the signal H.

F, F1 and F2 represent polarized relays, which are of high resista.nce,-for instance, 250 ohms.

G, Grjt and G2 represent batteries at the signals.

I represents a circuit closing contact, and K a reversing switch, both operated by the signal I-I. When the signal stands at danger, the position in which signal I-I is shown in the drawing, both switches occupy the positions shown at I and K. Then the home signal is clear, as shown at signal H1, the switches occupy the positions shown at I1 and K1.

g represents a common battery wire, t0 which the lower terminals of the batteries are connected through the neutral relay windings and the reversing switch.

c, c1 and c2 represent line wires, each eX- tending through a block and forming with the common battery wire g a circuit extending through each block.

A train is indicated diagrammatically at L in block A, while blocks A1 and A2 are clear. rlhe signals H and D are, therefore,

at danger, while signals H1, D1 and H2 are clear. The manner in which signals H1, D1 and H2 were cleared is as follows: when the train entered block A, short-circuiting track relay B, a circuit was closed from the upper terminal of battery G1, through the upper contact of reversing switch K1, which was then in the position shown for switch K, through the front contacts of track relay B1, line wire c, back contacts of track relay B, common battery wire g, lower contact of switch K1, and neutral relays E1 and C1 to the lower terminal of battery G1. The resistance of this circuit was low enough to energize both relays C1 and E1.l The former relay in closing its contacts established the operating circuit for signal H1 and cleared that signal. H1 cleared, switch l1 was moved to its closed position, as shown, while switch K1 was snapped over to the position in which Vit is shown in the drawing. The movement of switch K1 had no effect, but by the closy a circuit was established:

ing of switch I1 from the upper terminal of battery G1, through the upper cont-act of reversing switch K2, which was then in the position shown for switch K, through the front contacts of track relay B2, through contact l1,

contact of relay E1, winding of polarized relay F1, common battery wire g, lower contact of reversing switch K2, neutral relays E2 and C2, to lower terminal of battery G1. i Contact I1 and contact of relay E1 thus established a circuit shunting the'back con-v tacts of relay B1. The high resistance winding of polarized relay F1 is, however, included in this shunt circuit, s0 that the amount of current that flowed, while suflicient to energize neutral relay C2 to clearV homev signal H2,was not suicient to energize v relay E2, so that the clearing of signal H2 and the closing of contact I2 did not establish any i shunt circuit around the back contacts of. relay B2. Relay E2 thus acted as a meansfor preventing the establishing of such al shunt circuit when the home signal H2? cleared. Before the clearing of signal H2, the current flowing through the circuit, which has Just been traced, was in the wrong Vhen the signalV direction to energize polarized relay F1. Vhen, however, the signal lll2 cleared, shifting reversing switch K2 to the position shown,'the current in polarized relay i 1 was reversed, so as to cause that rela-y to close its contacts, and to clear distant signal D1.

The signals remain in the position shown until the train enters block A1, when the shunting of relay B1 opens the circuit ef relays C1 and E1. rlhe former relay opens the circuit of signal H1, while the latter relay, by opening the circuit of polarized relay F1, opens the circuit of the distant signal D1.

I do not desire to limit myself to the particular connections here shown, but aim in the appended claims to cover all modifications which are within the scope of my invention.

lVhat I claim as new and desire to secure by Letters Patent of the United States, is,

1. ln a normal danger block signal system, in combination with closed track circuits and track relays having front and back contacts comprised therein, signals for the blocks adapted to indicate danger, caution and clear, a relay for each block controlling the signal for the block and controlled by a front contact on the track relay for that block and a back contact of the track relay for the block in the rear, a contact controlled by the movement of a signal from danger, a shunt circuit for the back Contact of the track relay for that block arranged to be closed by said Contact controlled by the signal so as to energize the relay in advance, and means for preventing the closing of the contact on the signal in advance from closing the shunt circuit for the back contact of the track relay in advance.

2f. In a normal danger block signal system, in combination with closed track circuits and track relays having front and back contacts comprised therein, signals for the blocks adapted to indicate danger, caution and clear, a neutral relay for each block controlling the movement of the signal from danger toward caution position and controlled by a front cont-act on the track relay for that block and a back contact of the track relay for the block in the rear, a contact controlled by the movement of a signal from danger, a shunt circuit for the back contact of thetrack relay for that block arranged to be closed by said contact controlled by the signal so as to energize the neutral relay in advance, a polarized relay controlling the movement of the signal from caution toward clear position and having its winding included in said shunt circuit, meanscontrolled by the movement from danger of the signal in advance for reversing the current in said polarized relay winding, and means for preventing the closing of noemen the contact on the said signal in. advance :from closing the shunt circuit `for the back contact of the track relay in advance.

3. ln a normal danger block signal system, in combination with closed track circuits and track relays having front and back contacts comprised therein, signals for the blocks adapt-ed to indicate danger, caution and clear, a pair olf neutral relays for each block responsive to dilerent current strengths, the relay responding to the lesser current being arranged to control the movement of the signal for the block from danger toward caution position, a circuit :tor each of said pairs of relays extending through the block in the rear, said circuit including a low resistance connection for completing the circuit which connection is controlled by a back contact of the track relay in the rear, a contact controlled by the movement of a signal from danger and a high resistance connection for completing said circuit controlled jointly by said contact for the signal for the block in the rear and by a contact of the neutral relay l'or the block in the rear responding to the greater current.

l. ln a normal danger block signal system, in combination with closed track circuits and track relays having front and back contacts comprised therein, signals for the blocks adapted to indicate danger, caution and clear, a pair of neutral relays for each block responsive to different current strengths, the relay responding to the lesser current being arranged to control the movement ol' the signal for the block from danger toward caution, a circuit for each of said pairs of relays extending through the block in the rear, said circuit including a vlow resista-nce connection for completing the circuit which connection is controlled by a back contact of the track relay in the rear, a contact controlled by the movement of a signal from danger a high resistance connection for completing said circuit controlled jointly by said Contact for the signal for the block in the rear and by a contact of the neutral relay for the block in the rear responding to the greater current., a polarizedV relay having its windings included in the high resistance connection and controlling the movement of the signal for the block in the rear from caution toward clear, and a reversing switch in said circuit controlled by the signal mechanism in the iirstn'ientioned block.

5. ln a normal danger block signal system, in combination with closed track circuits and track relays having front and back contacts comprised therein, signals for the blocks adapted to indicate danger, caution .and clear, a pair of neutral relays for each block responsive to dillerent current strengths, the relay responding to the lesser current being arranged to control the movement of the signal for the block from danger toward caution, a polarized relay of high resistance for each block controlling the n'ioven'ient of the signal from caution toward clear, a circuit extending through each block including a source of current, a back contact of the track relay ol3 that block, and the windings of the neutral relays and a front contact or' the track relay ior the block in advance, a reversing switch controlled by the signal mechanism of the block in ad 7ance included in said circuit, a contact controlled by the movement of the signal from danger and a shunt circuit for the back contacts of each track relay including said contact controlled by the signal, a contact oi" the neutral relay responding to the greater current, and the winding of the polarized relay for that block.

G. ln a railway signaling system, a plurality of block sections, a closed track circuit for each block section each comprising a track relay having a front and a back contact, a signal for each block section, two relays fo-r each block section responsive to diiferent current strengths respectively, the relay responding to the lesser current being arranged to control the signal 'for the corresponding block section, a circuit for each block section including the two relays of the block section, the front cont-act of the track relay .tor the block section and a source or' current, said circuit also including a. low resistance connection for closing the circuit, each oi' which connections is controlled by the back contact of the track relay for the preceding block section, and a high resistance connection for closing the circuit each of which connections is controlled by a contact oi the relay for the preceding block section responding to the greater current.

T. ln a railway signaling system, a plurality ol block sections, a closed track circuit l'or each block section each comprising a track relay having a front and a back contact, signals for the block sections adapted to indicate danger, caution and clear, two neutral relays for each block section responsive to different current strengths respectively, the relay responding to the lesser current being arranged to control the movement of the signal for the corresponding block section from danger toward caution position, a polarized relay for each block section each arranged to control the movement of the signal for the corresponding block section from caution toward clear position, a circuit for each block section including the two neutral relays of the block section, the trent contact of the track relay for the block section and a source ol' current, said circuit also including a low resistance connection for 10 preceding block section, and a pole changing switch included in each circuit and controlled by Jche signal for the corresponding block section.

In Witness whereof, I have hereunto set my hand this 31st day of July, 1908.

ELMER F. BLSS.

Witnesses BENJAMIN B. HULL, HELEN ORFORD;

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,y Washington, D. 0. 

